Next: Organization of Data Sets in Virtual Observatories . ... Pasian, F. & Benacchio, L. 2003, in ASP Conf. ... The Italian Data Grid for Astrophysical Research (DRACO: Datagrid for italian Research in Astrophysics and Coordination with the virtual Observatory) is a concept having the aim of providing the scientific community with a distributed multi-functional environment allowing the use of specialized (computing, storage, observational) Grid nodes. ...